Pixel Circuit Having Threshold Voltage Compensation and Method for Driving the Same

1. A pixel circuit, comprising a resetting sub-circuit, a charging sub-circuit, a driving sub-circuit and a light emitting device, wherein a first terminal of the light emitting device is connected to a second voltage terminal; the driving sub-circuit comprises a driving transistor, a first transistor, a third transistor, a first storage capacitor and a second storage capacitor, wherein a source of the driving transistor is connected to a drain of the first transistor and a source of the third transistor, a drain of the driving transistor is connected to a second terminal of the light emitting device, a gate of the driving transistor is connected to a first terminal of the first storage capacitor; a source of the first transistor is connected to a first voltage terminal, and a gate of the first transistor is connected to a first terminal of the second storage capacitor; a second terminal of the second storage capacitor is connected to a reference voltage terminal; a drain of the third transistor is connected to the gate of the driving transistor, the source of the third transistor is connected to the source of the driving transistor, and a gate of the third transistor is connected to a first scan signal line; the resetting sub-circuit discharges the first storage capacitor and the second storage capacitor under a control of a first scan signal outputted from the first scan signal line; the charging sub-circuit comprises a fifth transistor and a sixth transistor, a source of the fifth transistor is connected to a data voltage input terminal, a drain of the fifth transistor is connected to a second terminal of the first storage capacitor, and a gate of the fifth transistor is connected to a second scan signal line; a gate and a source of the sixth transistor are connected to the second scan signal line or connected to a third scan signal line, and a drain of the sixth transistor is connected to the first terminal of the second storage capacitor.

2. The pixel circuit of claim 1 , wherein the resetting sub-circuit comprises a second transistor and a fourth transistor, a source of the second transistor is connected to the gate of the first transistor, a gate of the second transistor is connected to the first scan signal line; a source of the fourth transistor is connected to the second terminal of the first storage capacitor, a drain of the fourth transistor s connected to the reference voltage terminal, and a gate of the fourth transistor is connected to the first scan signal line.

3. The pixel circuit of claim 2 , wherein a drain of the second transistor is connected to the reference voltage terminal; or a drain of the second transistor is connected to the source of the fourth transistor.

4. The pixel circuit of claim 2 , wherein all of the driving transistor, the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor and the sixth transistor are N-type field effect transistors.

5. A method for driving the pixel circuit of claim 3 , comprising: during a resetting phase, turning on the second transistor, the third transistor and the fourth transistor through the first scan signal line, such that electric charges stored in the second storage capacitor are released, electric charges stored in the first terminal of the first storage capacitor are released through the third transistor, the driving transistor and the light emitting device, and electric charges stored in the second terminal of the first storage capacitor are released through the fourth transistor; during a compensating phase, turning off the second transistor, the third transistor and the fourth transistor through the first scan signal line, and turning on the fifth transistor through the second scan signal line, such that the first storage capacitor is charged by the data voltage input terminal through the fifth transistor; and turning on the sixth transistor through the second or a third scan signal line, such that the second storage capacitor is charged; during a light emitting phase, turning off the second transistor, the third transistor and the fourth transistor through the first scan signal line, turning off the fifth transistor through the second scan signal line, and turning off the sixth transistor through the second or the third scan signal line, such that the first transistor is turned on by electric charges stored in the second storage capacitor, and the driving transistor is turned on by electric charges stored in the first storage capacitor to drive the light emitting device to emit light.

6. The method of claim 5 , wherein during the resetting phase, releasing electric charges stored in the first terminal of the second storage capacitor through the second transistor so that the first transistor is turned off; or releasing electric charges stored in the first terminal of the second storage capacitor through the second transistor and the fourth transistor so that the first transistor is turned off.

7. The pixel circuit of claim 1 , wherein the light emitting device is an organic light emitting diode.